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1976 Fiat Spider 124 EV Conversion

15K views 81 replies 16 participants last post by  floydr 
#1 ·
Donner Car: 1976 Fiat Spider 124. Objective: Get my feet wet in the EV world and give me something to occupy some of my time in retirement. Challenges: Limited space, one spot in a three car garage in new house covered by a strict HOA. Advantages: Significant experience with large DIY projects. Built two vacation homes, built and flown experimental aircraft, car restoration, motorhome conversion and many other electrical mechanical systems. Background: Retire Lockheed System Engineer with AS and BS EE degrees. Age: 73. Location: Windsor Colorado

I want to build a low cost EV that is simple and performs similar to that of the 124 with the ICE. Range about 30 miles and used on relatively flat city streets with occasionally highway driving. Present design is 48 VDC Series Shunt Forklift motor of about 15 HP through the original 5 speed transmission and driven from a PWM controller from a 72 VDC LiFePo4 battery pack. No drive hardware obtained yet, still open to different technology. I intend to include significant instrumentation to monitor and document performance.

Additional information in "New Member" thread.

I intend to update this thread as I progress along with the project. Provide details on the design and lessons learned. I encourage input from the forum especially on simpler low cost approaches.

View attachment 133420
Striped down waiting for initial drive train.
 
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#3 ·
Looking at kits from electro motor sports. Trying to go inexpensive but get reasonable performance. Either DC Brushed as in the ME1008 or PMSM as in the ME1507 or ME1302. Comparing electric motor torque curves against the Fiat 124 ICE torque curve indicates to me that the ME1302 may not cut it where the ME1507 and ME1008 might be OK. The only issue I found in the forum was against the ME1008. The comment was that the ME1008 would not last long in a car. Initial recommendation from one member was that the ME1302 would be ok. I expect the final weight of the car would be near 2400 lbs. I am looking for comparable performance as with the ICE. Range near >15 miles initially. Anyone have a comment or recommendation.
 
#14 ·
Trying to go inexpensive but get reasonable performance. Either DC Brushed as in the ME1008
You might check out this post dual ME 1003? motor set up for an idea of what can be done if your are inclined, Note in the article on the Miata conversion the motors are identified as ME1007's But the motors are vented which would be a ME1003? Unless the brush covers were changed.
Later floyd
 
#5 ·
DC forklift motor - 15 hp so probably an 11 inch motor

I would suggest simply using the motor in place of the gearbox - which will leave the engine bay for batteries

You will need to increase the voltage - you need about 150 volts for street use
You will need about 500 amps to give useful torque

DC forklift motors are old obsolete technology - but they are cheap and powerful

IMHO the sensible options are the old DC forklift - OR - the power unit from a modern EV

The "new kits" are both very expensive and gutless

Motor Voltages
My motor (Hitachi) is badged at 48 volt - but I'm feeding it 340 volt
That is a bit extreme but 150 volts will be no problem
 
#6 ·
Dc brushed is kinda 1940 technology anymore unless you want to build your own pwm controller. Ten years ago, it was all you had for parts......or you had no money.......new automotive motors are multiphase, more efficient, and do regen. Jury is out on the ME series of motors, there's better available now. Someone indicated the hyper9 was induction, I don't know.

Might want to see if you can work on your car, some HOA's say "nope".

Having built your own plane means you understand the labor of love your undertaking.
 
#7 ·
HOA saids OK as long it is in the garage. Partial to a DC motor because it is cheep and I can use just a cheep basic controller initially. I want to get things going to get hands on experience with a 8 -12v 100 ahr battery pack (72v). If things work I would switch to LiFe and 96V to get extended range, higher speed with the about the same weight. I got the lead acid batteries from a solar project I was working on in CA. By the way I intend to use the batteries in the car as house backup. Charge from the sun, charge from the line, drive the car. If there is a power outage use the car batteries to power the house through an AC inverter. More bang for my buck. Piotrsko do your comments on DC motors still apply to a permanent magnet motor like ME1008? Has any one on the forum heard any good or bad thing about the ME1008, especially powering a 2400 lb car?
 
#10 ·
Piotrsko do your comments on DC motors still apply to a permanent magnet motor like ME1008?
Whether a DC motor has field windings in series with the armature ("series"), or field windings in parallel with the armature ("shunt"), or field and armature separately controlled ("SepEx"), or no field windings at all because it has permanent magnets instead, the motor still depends on brushes and a commutator to operate the armature; the characteristics do change (including the ability to regen with a suitable controller), but whether they are suitable for a given application or not depends very much on individual motor choice.

The ME1008 (and ME1007) seems like a strange design to me: it is apparently totally enclosed, so it isn't cooled by air passing through it, but it has no other cooling provisions (external fins and fan, liquid cooling, etc).
 
#8 ·
Make sure you can get that "cheap" DC controller - a lot of people can't get the components to build your components, and, because they cannot, what was "cheap" no longer is. Same story for motors, as has been stated in another thread where they can't get a bearing to produce a motor.

The world made a mistake relying on Chinese manufacturing - and when it got buyer's remorse, the Chinese made sure the world could not get the pieces needed to repatriate manufacturing. There are no parts shortages for BYD and others making EVs in China...Musk is now talking about importing Shanghai-made Teslas to the US, so time to whack them with a 30% tariff.
 
#11 ·
Sounds bad. Will we have to regress back to the 20s and use carbon piles, high current knife switching and lead acid batteries. Our power infrastructure is not going to take that type of inefficiency, Ha Ha. Yea, lets stop hydro carbon drilling.

Well, I am still looking for a motor.
 
#13 ·
Talking to a commercial water well servicer: there are cheap used (pulled working but scrap value), multi phase ( he hinted at variable speed ?) AC controllers for water wells up to 100hp, but the down side is they are generally 408 volts 3ph. He thought there might be DC capable controllers. Did not verify this claim. Worst case is you can use the power silicon and the control scheme.

Over in the for sale section here there's usually a couple of controllers for sale, but buyer beware, Singapore merchants on the internet have proven to be more honest and forthright. Might be worth it to aquire the controller and let that dictate the powertrain
 
#16 ·
Seriously considering the ME1507/ME1905. It is a 96 volt system. Talk to Electro Motor Sport and they recommended that system. Attached picture of the Spider motor bay. Transmission is supported by itself and there is plenty of room for the motorwith good support. The interface plate is not in place. I am waiting until I know what motor I will use before I cut the plate. Motor vehicle Hood Automotive tire Automotive exterior Vehicle
Should be a clean installation with plenty of room for batteries.
 
#17 ·
Seriously considering the ME1507/ME1905. It is a 96 volt system. Talk to Electro Motor Sport and they recommended that system.
The ME1507 and ME1905 were not in my earlier list of Motenergy models, because they're not the brushed PM type that was being discussed. The ME1507 is an enclosed (to IP65 standard) air-cooled brushless radial-flux PM motor; that seems inherently preferable to any brushed motor to me, for similar size and other ratings.

Motenergy doesn't even list the ME1905 on their web site, so it's not clear what the difference might be.
 
#19 ·
Coming along with the car conversion. Built the motor to trans interface and testing with a small 24V 3 HP peak motor running on 36 volts with a Curtis 275 amp controller. Looks like the interface performs well, but only time on the road will tell.
I am gong to mount into the car just for the fun of it to see what the motor can do. 10 mph in first? Will measure the amps dawned. Probably get a 72 V PM motor from Electrosport, ME1908 with 19Hp peak at 72 volts. Thinking about lead acid batteries with a total 7.2 Kw AH pack. Hope with this arrangement I can get 10 miles level ground with 50% discharge. Into the project $2300 including donor car. Expect another $2500- $3500 for batteries, motor and controller. If this setup works out and I like the car I may spring for an AC motor system from Electrosport in the future. My primary purpose right now is to hands on learn about EV systems and have fun building. I am working on full instrumentation for this setup. Fun to plot the data and evaluate the results.
 
#23 ·
I will check out the Leaf battery. Are you talking about a new or used leaf battery? Right now for my testing and learning phase I was just going to get $1,200 of lead acid batteries. Use them later to replace batteries that go bad in other cars because of the Colorado cold. Also, I am spreading out my costs over time. Yes, I know all batteries are DC, but I did not want to invest in a larger battery that would give me more range until I go to the AC system. What do you think of the Jaw coupling to the transmission? I went with it because of possible misalignment between the motor and transmission. For testing purposes I expect to do less than 100 miles. In that distance I should be able to evaluate ware.
 
#28 · (Edited)
What do you think of the Jaw coupling to the transmission? I went with it because of possible misalignment between the motor and transmission.
The "Jaw coupling" ( Lovejoy type coupling?) needs both shafts it connects rigidly supported by bearings. The input shaft of the typical, common transmission, as it looks like the 124 has, is not well supported inside the transmission. You may have noticed it has a lot of side to side play. Typically, with an ICE, a carefully located pilot bearing is used at the end of the input shaft to align and support it. This pilot bearing is located in the end of the crankshaft or in the center of the flywheel.

The input shaft center line needs to be located within 0.005"(according to most manufacturers) from the transmission center line to prevent damage to the gears and bearings inside the transmission from misalignment. A Lovejoy type coupling will not support the input shaft and align it with this kind of accuracy. If you use one, be prepared to have to replace this expensive and rare transmission after a short period of time, as others have found with similar types of transmissions with poor input shaft support and misalignment issues.
 
#24 ·
Just an FYI:
In Lead Acid batteries there are (2) main types
...& they are designed for (2) very different uses

Starter batteries are used to "start" car engines (for short bursts)
...& Deep Cycle batteries are used to "power" electric motors (for long term/continuous use)

So, Starter batteries are not very "good" for long term power draws
...& Deep Cycle batteries are not usually very "good" for starting car engines

As another example, of available OEM Lithium battery packs, complete (used) 360V Chevy Volt Lithium battery packs are usually available for ~$2,000.00 on car-part.com
...& will "power" most DIYEV's very well ;)
 
#25 ·
Plan on zero misalignment between the two. Things you can't control, like temperature changes is why the coupler is there...not to enable a sloppy build. Jaw couplers suck, imo, but that's imo.

Check in with @windraver - he may have a set you can get. You won't pay much more, if any, than lead acid, you'll get more range, and a lot less weight which is a huge problem in any build.
 
#27 ·
Still learning
Me too ;)

As for Lead vs Lithium in an EV

When I first converted my ElMoto (electric motorcycle), I used (4) 12V 35AH Lead Acid batteries (~140lbs.)
...& my range was only ~9 miles

Then, when I upgraded to a 48V 50AH Chevy Volt Lithium module (~50lbs.)
...my bike seemed "more nimble" from the (~90lbs.) weight loss
...& my range increased up to ~25 miles :cool:
 
#29 ·
So the Jaw coupling will not work for the long run. I was wondering why the need for the pilot bearing. It was always a pain to get the transmission slid into the flywheel even with a clutch disk centering tool. There are other 124s that have been electrified. How did they connect the motor to the transmission? The electric motor should have a front bearing. Will it support the side/up/down play of the input shaft of the transmission? I guess I need to get a ridged coupling and get as precise alignment as I can get. I will have to do a lot more research on this. This is why I have not spent big bucks yet on batteries and a motor system. Maybe the 124 is not a good candidate for my effort. Is there some way of telling that your misaligned? Noise or vibration? If so than maybe some careful left/right/up/down adjustment to tweak the alignment. Than match drill in place. The mechanical aspect is not as simple as I though. Well I will continue with the small motor and electrical setup I have for now with the Jaw coupling. Lots to think about.
 
#36 ·
There are other 124s that have been electrified. How did they connect the motor to the transmission?
They likely did what many conversions have done: they rigidly mount the motor to the transmission, and do not use any flexible couplings.

The electric motor should have a front bearing. Will it support the side/up/down play of the input shaft of the transmission?
Yes, it is common to mount a flywheel and clutch assembly on a motor with no support of the shaft other than the motor's own bearings, and to pilot the transmission shaft in that assembly. Don't assume that this will work with every motor, but it typically works with motors based on industrial designs (including old forklift trucks) with protruding plain shafts.

I guess I need to get a ridged coupling and get as precise alignment as I can get.
Yes, that's the general best practice. The coupling can have rotational compliance (like the spring centre of a clutch disk), and may slide axially (depending on design details) but not radial compliance.

Maybe the 124 is not a good candidate for my effort.
There's nothing unusual or especially difficult about the 124 as far as connecting a motor to the transmission is concerned.

The mechanical aspect is not as simple as I though.
That's a common situation: people with electrical experience don't realize that the mechanical parts are not trivial; people with mechanical experience don't realize that the electrical parts are not trivial. Software people don't understand high-power and high-voltage electrical issues, while electrical or electronic hardware people don't appreciate the complexity of software systems. Even when working in their own fields, people don't anticipate that their own experience might not completely cover new applications.

Well I will continue with the small motor and electrical setup I have for now with the Jaw coupling.
I don't think that's advisable.
 
#30 ·
One of the best options is to get a commercial adapter plate and coupling such as those made by can EV(possibly others) and supplied by their retailers: -- Vehicle Adapter Plates - - Motor Mounts / Adapters - MOTORS - EV PARTS . Although, I don't see one for a Fiat listed. An option would be to switch to a transmission from a more common vehicle (Toyota, Nissan, Ford, GM,etc.) that has an adapter plate and coupling available.

It looks like this Fiat transmission has a separate bell housing that has a machined circular hole where it aligns with the main body of the transmission. If so, this hole could be used with a dial indicator to align the electric motor output shaft on a fabricated adapter plate. This process is similar to how an ICE is set up: How To Align Your Bellhousing For Maximum Transmission And Clutch Life Unfortunately, most modern transmissions don't have a separate bell housing with this alignment option.

Rather than relying on the varying tolerances of regular bolts for repeatable alignment of the adapter plate on the bell housing, reamed holes with close fitting dowels should be used- just like the OEMs and the commercial adapter plates above use.

The coupling should have some provision for a pilot bearing or bushing to support and align the end of the input shaft.
 
#31 ·
The jaw coupling will not work in the short run either. Wrong application.

You need a coupler and motor mount that's designed to be aligned as a system, ideally with that pilot bearing centered on the motor shaft.

There will be machining needed -- you are not going to pull a solution out of your HobbyKing catalog. Ditch the RC-car engineering.

Don't know what you mean by "rigid coupler".
 
#32 ·
Throw the gearbox over a hedge - its not needed - your problem with a low voltage system will be rpms - not torque
and a gearbox operates by gearing the motor down

When I was starting out I planned on using a Ford gearbox - but some quick calculation showed that I simply would not need the gearing
In "top gear" even with a small controller I was getting close to the "spin the tyres" torque

Without the gearbox you simply need to attach the propshaft to the motor - and with the motor where the gearbox used to live you will have lots of unobstructed space under the bonnet for batteries
 
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